Field of the Invention
The present invention relates to an image display apparatus, a control method of an image display apparatus, and a program, and specifically relates to an image display apparatus and an image display method that are suitable for browsing structured image data with other viewers by sharing a screen.
Description of the Related Art
There is a technique in which image data is displayed by using such as a projector or an electronic blackboard, and data that is input by handwriting in real time (referred to as “annotation data”, or simply “annotation”) is displayed superimposed on this displayed image data. Japanese Patent Laid-Open No. 2014-004783 discloses a technique of increasing a transmittance of the annotation with the increase of the elapsed time after the annotation is input if the annotation is displayed superimposed on the image data displayed on the screen such as the electronic blackboard. Accordingly, old annotations gradually fade in accordance with the elapsed time, and if new annotations and the old annotation are overlapped, a viewer of the screen can easily focus on the new annotations.
However, image data that successively changes its display is included in the image data. As an example of the image data that successively changes its display, there is a page in which “animation in presentation application” is set. A plurality of objects included in such a page are focused in order according to a user's operation, and displayed on the screen. Additionally, as another example of the image data that successively changes its display, there is also image data in which an object specified by the user is focused on and displayed on the screen, among the plurality of objects included in the page.
In addition, the following methods serve as examples of the focus-display: a method for displaying an object at a display magnification corresponding to a size of the object to which attention is to be paid; a method for displaying the object to which attention is to be paid with highlights and displaying other objects in grayout; and a method for visibly displaying the object to which attention is to be paid that has been hidden (has been invisible).
Here, it is contemplated that the annotation is entered for the supplemental explanation of the object if an object among the plurality of objects included in the page is being focus-displayed. Such kind of annotation is desirably displayed during the focus-display of the object that is a target of the supplemental explanation. However, in the Japanese Patent Laid-Open No. 2014-004783, even such a kind of annotation may gradually fade in accordance with the elapsed time. Additionally, if the annotation is entered while changing the area to be displayed with attention (the area to be focus-displayed), there are cases in which the annotations are displayed superimposed on the area to which attention is to be paid, or the viewer will pay attention to an area different from the area where a presenter wants the viewer to pay attention.